Hundreds of thousands of trees died in the historic drought of 2012, and many more will succumb in the next few years, scientists say.

“This is just beginning,” says Janna Beckerman, a plant pathologist at Indiana’s Purdue University. “I suspect we’ll see trees still dying for the next two or three years.”

Indiana’s white cedar and Florida cypress trees began dying in late summer, she says, and Alberta and Colorado blue spruce are succumbing now.

Trees affected by a 2010-11 drought still are dying across Louisiana, says Keith Hawkins, a Louisiana State University AgCenter forester. Some trees “reached a threshold from which they can’t recover — especially older, larger trees,” he says.

About 301 million trees died in rural Texas because of that drought, the Texas A&M Forest Service says.